Titanium based porous cathode materials for lithium-oxygen batteries

Conventional cathode materials in lithium-oxygen batteries suffer from degradation and therefore diminish the cycling efficiency of these promising future energy storage systems. Amongst fighting such degradation by other means [1], titanium carbide (TiC) based electrode materials were shown to resist the harsh reaction conditions in Li-O2 cells [2]. However, high capacities can only be obtained when highly porous electrode materials are employed. Herein we demonstrate a Ring-opening Olefin Metathesis Polymerization (ROMP) based way for the preparation of hierarchically porous TiC on carbon with BET-surface areas of approx. 450 m2/g. The synthetic route comprised emulsion templating of dicyclopentadiene [3], curing of the emulsion via ROMP, oxidation of the resulting monolith, filling of the pore structures with a Ti-monomer, a second ROMP step, and finally carbonization at 1400°C. The resulting conductive TiC foams were shown to be superior cathode materials in Li-O2 batteries in comparison to similarly prepared carbon foams and TiC nanoparticles.

[1] Mahne, N.; Schafzahl, B.; Leypold, C.; Leypold, M.; Grumm, S.; Leitgeb, A.; Strohmeier, G. A.; Wilkening, M.; Fontaine, O.; Kramer, D.; Slugovc, C.; Borisov, S. M.; Freunberger, S. A. Nat. Energy 2017, 2, 17036; [2] Ottakam Thotiyl, M. M.; Freunberger, S. A.; Peng, Z.; Chen, Y.; Liu, Z.; Bruce, P. G. Nat. Materials 2013, 12, 1050; [3] Kovačič, S.; Matsko, N. B.; Jeřabek, K.; Krajnc, P.; Slugovc, C. J. Mater. Chem. A 2013, 1, 487.